Fundamentals of dry reagent chemistries: the role of enzymes

It is evident that the specificity and catalytic efficiency of enzymes has revolutionized clinical diagnostics. Developing dry reagent systems provides convenience to the user as well as devices that are more versatile and suitable for a variety of analyses. Most dry reagent chemistries are usually less than 7 cm2 x 300 microns thick and are packaged as discrete test devices, which reduces spoilage of unused reagents. Sample volumes needed for analysis are usually in the range of 3-30 microL; the 10-microL volume is most commonly used. The use of such small volumes makes these devices suitable for neonatal and geriatric patients where large sample volumes are not often available. Hence, 150 microL of serum (approximately 300 microL of blood) is sufficient for at least 15 different analyses on a sample. Dry reagent chemistries are easy to store, readily available for use, and disposable. Only application of a sample is needed to start an analysis.